With dorsal spines that managed to stay three dimensional even after 500 million years of geological activity, Collinsium was one particularly prickly invertebrate. Like her modern kin (velvet worms), she possesses Matryoshka doll style claws (and in her case, also spines) composed of layered chitin, the same carbohydrate that forms arthropod exoskeletons. Unlike velvet worms though, her kind were far more diverse in lifestyle and ecological niche. She, in fact, was a bona fide filter feeder and lacked eyes altogether (Those are armor plates before her antennae). The glory days of stem-Onychophora would come to an end by the end of the Cambrian, though. Onychophora has now dwindled down to just the velvet worms, all of them active terrestrial predators inhabiting humid environments.